Of the on-time returns, 7.93 million (82.5%) were sent online – a record number. The remaining 1.68 million (17.5%) were sent on paper.

As expected, many left their submissions to the last minute, with the busiest day for online returns being 31 January, when the taxman received 578,000. The busiest hour was between 4pm and 5pm on 31 January, when 46,000 returns – more than 12 per second – were received by HMRC.

In the run-up to the deadline, a record 1,548 made their filing on Christmas Day, while 4,685 followed suit on Boxing Day. Another 27,161 filed online on New Year's Eve, with 12,077 submitting their return on New Year's Day.

Anyone filing late has already incurred £100 late-filing penalty. After that, daily £10 fines up to £900 are also in place if the taxpayer has not paid up to three months after the deadline. Should six months elapse with no payment, an additional penalty of £300 or 5% is imposed, whichever is higher. After a year, a further £300 or 100% of tax owed is imposed.